The Pennsylvania Turnpike Commission plans to convert its present interchange-numbering system to a dual system that will incorporate milepost designations along with existing interchange numbers on roadway signs.

For example, the Harrisburg East Interchange, currently number 19, will become Interchange 19/247 because it is located at milepost 247.3 on the Turnpike. In each case, the tenth of a mile will be dropped in favor of a whole number.

The names of the Pennsylvania Turnpike’s 58 interchanges will remain the same.

The dual-numbering system will be more convenient and helpful for travelers, and it will also allow the Turnpike to begin to conform to Federal Highway Administration standards.

"Dual numbering makes it easier for our customers to calculate travel times and distances," said Turnpike Executive Director John Durbin, noting that an Ohio Turnpike survey revealed that motorists prefer the federal standard over the existing numbering method by a two-to-one ratio. "In addition, the changeover makes the Turnpike interchange numbers uniform with those on most other interstates."

Additionally, emergency personnel — such as police, firefighters, and ambulance squads — prefer the milepost method because of the ease in locating and responding to a crisis scene.

The Pennsylvania Department of Transportation plans to convert Pennsylvania interstates to the mileage-based system as well, and the Turnpike has scheduled its switch to coincide with PENNDOT. PENNDOT officials said customers have demanded the change for many years.

Modification of the interchange signage on the Pennsylvania Turnpike — which entails replacing the exit-number panel (tab only) on top of the signboards — is expected to begin in early spring 2001.

"The adapted signage, featuring both the existing and new numbering, will likely be in position across the Turnpike by Memorial Day," said Timothy M. Scanlon, P.E., the Turnpike’s traffic engineering manager, noting that the project is being completed at a cost of roughly $175,000.

Alteration of printed materials such as toll tickets and maps, as well as updated auxiliary guide signing, will be phased in over a four- to five-year period.

In concert with the dual-numbering initiative, Turnpike maintenance crews are upgrading all tenth-mile markers that can be seen on the shoulder of the Turnpike and its extensions. New high-visibility tenth mile markers are now being installed on the entire 512 miles of roadway to allow customers to more easily determine their precise location.

The more than 10,000 new tenth mile markers feature bold white print that is two-times larger than the existing numbering on a highly reflective green background. The markers, which are also eight inches taller than the existing tenth mile markers, are made of a flexible material that springs back up when run over, according to the Turnpike’s Director of Maintenance Robert M. Wallett.

Wallett also said that — due to the bright green reflective material — motorists will be able to better distinguish the tenth mile markers from the standard white delineation markers with white reflective stripping.

The cost for the new mile markers is around $210,000.